THEIR STRUCTURE. 195 



sule, the process being all over in about a minute. 

 To my surprise they were neither medusoids, nor 

 ciliated planules, but soft gelatinous inanimate eggs, 

 closely like those of Rotifera, without the least 

 appearance of cilia, or of spontaneous motion (Fig. 7). 

 They all sank immediately to the bottom of the glass 

 cell, and remained motionless, as far as respects 

 change of place. But after several hours I perceived 

 that each egg was undergoing a constant change of 

 shape, reminding me of those alterations of outline 

 seen in the Ammba among Infusoria. Sometimes a 

 constriction would appear across one end of an egg, 

 which would move towards the middle, cutting it into 

 two portions, then be slowly obliterated. Or from 

 some point in the circumference little swellings would 

 protrude, and these I have reason to think separated, 

 for though I did not actually see this done, I saw 

 several small globules lying, by, of exactly the same 

 substance and colour as the ova themselves. Or an 

 Qgg would imperceptibly become from round to oval, 

 thence to pear-shaped, and thence assume some 

 irregular form, and gradually revert to its original 

 appearance. These changes were slow in operation, 

 but they indicate that the ovum remains soft and 

 shell-less, and that there is a principle of volition 

 within it. They one by one decomposed. 



THE bird's head CORALLINE. 



In one of the shallow pools near the base of Cap- 

 stone Hill, I took several beautiful specimens of one 

 of the prettiest of the Polyzoan polypes, Cellularia 



